const video = document.getElementById('video')

//使用Promise异步加载对应的训练模型，加载完成后打开摄像头
Promise.all([
    faceapi.nets.tinyFaceDetector.loadFromUri('./models'),
    faceapi.nets.faceLandmark68Net.loadFromUri('./models'),
    faceapi.nets.faceRecognitionNet.loadFromUri('./models'),
    faceapi.nets.faceExpressionNet.loadFromUri('./models')
  ]).then(startVideo)

  //让浏览器自动打开摄像头
  function startVideo() {
    navigator.getUserMedia(
      { video: {} },
      stream => video.srcObject = stream,
      err => console.error(err)
    )
  }

  //监听对应的人脸表情和模型数据进行比对
  video.addEventListener('play', () => {
    const canvas = faceapi.createCanvasFromMedia(video)
    document.body.append(canvas)
    const displaySize = { width: video.width, height: video.height }
    faceapi.matchDimensions(canvas, displaySize)

    console.log(1);

    // 比对好之后利用canvas进行绘制
    setInterval(async () => {
      const detections = await faceapi.detectAllFaces(video, new faceapi.TinyFaceDetectorOptions()).withFaceLandmarks().withFaceExpressions()
      const resizedDetections = faceapi.resizeResults(detections, displaySize)
      canvas.getContext('2d').clearRect(0, 0, canvas.width, canvas.height)
      faceapi.draw.drawDetections(canvas, resizedDetections)
      faceapi.draw.drawFaceLandmarks(canvas, resizedDetections)
      faceapi.draw.drawFaceExpressions(canvas, resizedDetections)
    }, 100)

  })
